We determined the effect of the removal of the phenolic hydroxyl group of opioids on antinociception, receptor binding affinity, and abuse potential. One of these compounds, 3,6-dideoxydihydromorphine was at least twice as potent as morphine, or dihydromorphine, as an antinociceptive. It appeared to have a dependence capacity very much like morphine in single-dose suppression studies in the rhesus monkey. Its binding affinity to the opiate receptor was about one-third that of morphine. Thus, the phenolic hydroxyl is not necessary for potent antinocicepive activity, nor for the development of physical dependence of the opiate-type. However, the phenolic hydroxyl does aid an opioid in binding to its receptor.